Build and flash coreboot.
Get the tarball that contains the generated code, extract it.
Also get the i915_regs.h header and put it in final/
Then go into i915tool(the official one, not the one in coreboot repository) and apply some patches for the x60 or redo them for your mainboard.

$ cd i915tool/x60

use picocom -b 115200 /dev/ttyUSB0 or stty to set the bauds of the Serial port.
Then get logs:

$ cat /dev/ttyUSB0 | tee coreboot.log

Then remove the binary symbols, dos2unix will help identifying where they are: